1. Field of the Invention
The present invention relates to a high capacity pneumatic spreader notably for powdered or granular materials.
The invention is applicable more particularly to spreaders whose spreader bars are borne by the main frame or chassis supporting the hopper designed for storing the material to be spread.
2. Description of the Prior Art
Conventional pneumatic spreaders which generally comprise a main frame mounted at one end on two rear wheels, a hopper resting on said frame and foldable spreader bars capable of being deployed laterally to spread the material, can be classified in two separate types according as the spreader bars are borne by a second frame coupled behind the frame supporting the hopper or as they are borne and folded directly to this hopper-supporting frame on each side of the latter.
British Pat. No. 1,435,999 and U.S. Pat. No. 2,657,949 fully illustrate the state of the art in the field of spreaders of the first type mentioned above whilst French Pat. No. 1,584,381 corresponding to British Pat. No. 1,271,738, to German Pat. No. 1,939,413 and to U.S. Pat. No. 3,568,937 is a good example of the field of spreaders of the second type mentioned above.
In spreaders of the first type, the surroundings of the hopper are clear on each side which facilitates considerably the loading of the latter with the substance to be spread, but the longitudinal bulk is large, notably during transportation when the ramps are folded back rearwards and add their length to that of the frame hopper-supporting frame and to that of the tractor.
In spreaders of the second type such as that forming the subject of French Pat. No. 1,584,381, the length of a second frame is economized by arranging for the spreader bars to be carried by the hopper-supporting frame and the approaches are kept free on the sides of said hopper but nonetheless the overall length of the whole still remains too great due to the fact that the spreader bars are folded back rearwards in extension of the frame. Attempt has already been made to overcome this drawback by raising the spreader bars upwards on each side of the hopper instead of folding them back rearwards, but with this solution, the spreader bars border the hopper laterally and for this reason interfere with loading from the side, this arrangement of the spreader bars on each side of the hopper resulting also in numerous other drawbacks such as, in particular, the risk of said spreader bars becoming damaged by the loading equipment loading from the sides so that it becomes necessary to load from the rear, which necessitates a reduction in the diameter of the transporting wheels so as to be able to approach the hopper, as a result of which there are high contact pressures with the soil which necessitate considerable pulling forces to move the spreader.
In addition, to remain within the highway gauge the thickness of the spreader arms only allows a reduced hopper width and, to keep a sufficient transportation capacity, it is necessary to increase the height of said hopper with the risk of reducing the stability of the whole.
Accordingly, it is an object of the invention to provide a spreader which does not have the aforementioned drawbacks.
It is another object to provide a spreader which permits side loading without however resulting in an increase in length or a reduction in the stability of the equipment.